So basically you are going to have to just roll with whatever the lighting techs throw at you. (obviously haha). In saying that there are a few things that may be your friend.

ISO - Two schools of thought here 1) crank it up! Forget about the "pixel quality" and just deal with the noise you are going to get with the high ISO, its going to give you a faster shutter speed meaning that the dancers won't be a blurred mess. The grainy look is fairly "in" with these sorts of photographs as well. 2) Keep the ISO as low as you can. So pick a shutter speed that you find acceptable and set the ISO from that. You will get less grainy images but more motion blur.

Lens Speed - Use your fastest lens. Perhaps borrow one if you don't have one. 2.8 is nice 1.4 is better haha. . . . obviously you only get the benefits if you use it wide open haha.

Spot metering - You may want to work with this. Stage lighting tends to play games with your TTL meter. IF your not sure on what this is and how to use it do some search's its a bit tricky for me to explain here.

Anyway hope that helped a bit. Hope I'm not just telling you stuff you already know! haha. If you have any specific questions just sing out

I've been asked to take photos at a dance concert and am a little bit worried about getting decent shots. I've never taken photos under this sort of lighting. Does anyone have any advice?

Sounds like you haven't taken photos in this sort of environment before, so, especially if you are being paid to take the photos, see if you can set up similar lighting conditions you expect in the largest room in your home (or somewhere similar) and play with the ISO and shutter speed settings to get the best exposure and least blur from moving dancers etc.

In relatively low lighting, you might have to use a tripod or fix your camera on something solid to eliminate "shake" and the consequent blurring.

Also, if you're not confident in getting the correct exposure, try playing with the AEB (Auto Exposure Bracketing) on your camera (before the dance concert of course).

Second, you need a large aperture on your lens, for example F1.8 or higher.A tripod could help aswel to have stability with longer exposures.You can experiment with long exposures for a nice effect, with a small aperture like F 22 and see the people smoothly dance like ghosts ?

Just keep in mind that a tripod will not help with motion blur, only camera shake. (it will stop static items from becoming blury due to movement of the camera. It will not help with moving subjects like people). Image stabilisation will help you here to. Giving you a extra stop or two.

if you have a professional camera you will be able to get excellent photos even under these light conditions, there are very good cameras from Canon, Sony and others. But first of all you need a additional flash light and as many pixel as you can get

I've done some stage/concert/performance photography. If you can get in for the sound/lighting check to get an idea of what you're getting into, or even better a dress rehearsal, you'll be better prepared for when you start. That will allow you to find the settings which will work best for you, and the environment.

For concerts I always shoot raw with noise reduction switched off at relatively high iso, as post production software can make a better job of noise reduction.

I also tend to under expose shots to get a faster shutter, and avoid blowing out face highlights in situations where the people on stage are well lit but surrounded by dark. If the stage is lit with primary colour lights you'll often blow out a single RGB channel. Again, it's easier to increase exposure in post than it is to retrieve blown highlights.

You can get some great directionally lit black and white conversions by using a single channel if the lightings like this, always worth quickly soloing channels in photoshop if you have it.

With regards to Leslie75 saying 'as many pixel as you can get' well depends on your choice of equipment but low light photography is generally best done with the largest sensor you can get, and lowest pixel density. Anybody who's ever used a nikon d3 or d4 (the best low light cameras available) knows that less pixels wins in the dark.

I often shoot manual if using a fast lens and time shots for performers to move into my preset narrow focal field (e.g in between songs will focus on the lead mic stand, tweak back a bit then fire of shots as the singer approaches the mic. This means I can get well timed shots rather than waiting for a focus lock which may be delayed if the the camera struggles to get a fix and 'hunts' in low light.

Everything depends on the camera equipment you will use, but as many already suggested push up ISO, use F/1.8-F/5.6, good if lens have optical movement stabilisation, switch it on.Most important to you is prevent camera shakes and use enough F to froze the movements on the stage. Good luck!

Since this question was asked last July and the last answer given last September, I don't see how much of anything will help the OP at this point. Please don't dig up old threads. If you have something valuable to contribute, please do so in an active thread or begin a new thread.